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Peer Domain System is a decentralized name resolution system which provides strong authentication and prevents name conflicts.


Basically, PDS keeps domain name data in .pdz or .pdr text files, which contain signed associations of domains to targets, which can be IPs, CNAMEs (aliases to other names, DNS- or PDS-based)...

These files are simple enough so that their domain associations can be easily spread by pasting their content on Twitter, discussion forums, web pages, emails, and so on. Users can simply copy a PDR text line found on a page and paste it on a text file inside the PDS application folder. Or they try to access a domain, and if it's not found among the currently available PDR files, the PDS client will automatically try to fetch it using Bit Torrent or a DHT-based map.

One of the design goals is to make it easy to share name resolution data.

Design Goals

Standard Syntax

To test the regexp, see

Full (or DRS) PDS identifier syntax: domain#revision@signer

DRS = Domain, Revision, Signer

That is, domain domain at revision revision signed by signer.

This can be put on a browser's address bar. The browser will query the local PDS client (which provides a standard DNS interface for applications, so that any current application can use it) for the target of that domain. See some response examples:

  1. openfarmtech#revision@signer has target
  2. domain#revision@signer has target (or points to) IP,
  3. domain#revision@signer has target (or points to) CNAME other-domain-being-aliased

One can also query a partial PDS identifier:

DS-type identifier syntax: domain@signer

This means the user wants the latest association for domain as reported by signer signer.

DR-type identifier syntax: domain#revision

This means the user wants the association for domain at a specific revision number as reported by the trusted signer for that domain. (Yes, users can configure the order of trusted signers for specific domains).

Instead of configuring trusted signers for a certain domain, the user can simply store a PDR file inside a folder named trusted. All PDR or PDZ files inside that folder will be blindly trusted (that is, signature checking won't be strict, so that you can use null signatures).

D-type identifier syntax: domain

This type of identifier is similar to the DR-type, but instead of requesting a specific revision, the user wants the latest revision for that domain.


domain = name:suffix

  • Domain to be resolved


  • regexp: /[a-z0-9][a-z0-9-]{2,998}[a-z0-9]/
  • a dash must not follow another dash
  • Examples:
    • openfarmtech
    • p2p-foundation


  • Helps prevent name conflicts; provides error checking.
  • Format: ABC where:
    • ABC must match /[a-zA-Z0-9]{3}/
    • The domain owner can only choose A and B
    • C is a checksum calculated over name:AB
    • If A is a letter, B must be a digit
    • If A is a digit, B must be a letter
    • Some valid examples:
      • b4c
      • b4C
      • B4c
      • B4C
      • 4bc
      • 4Bc
      • 4bC
      • 4BC
      • b47
      • B47
      • 4b7
      • 4B7
    • Some invalid examples:
      • bc5
      • bcr
      • Bcr
      • 45c
      • 45r


Like an SVN revision number. Every time the domain owner chooses to update his domain (that is, choose another target for the


Identifies the public key that should be used to check the signature


  • DHT key 1: (name, suffix)
  • DHT key 2: (name, suffix, signer)
  • DHT key 3: (name, suffix, signer, revision)


  • signer: How to get the signer's public key?


  • 3 levels (name:suffix#revision@signer)
    • openfarmtech:4h#5@elifarley
  • 2 levels (name:suffix):
    • openfarmtech#4H
  • 1 level (name):
    • openfarmtech


revision should be serial or date?

DNS-style syntax



  • openfarmtech.p2p

Image Syntax

Encode PDR using QR code / SPARQCode ( a 2D barcode).

TODO Experiment with various 2D barcodes at the Online Barcode Generator

Date format

See wikipedia: Base32 Let's use z-base-32: human-oriented base-32 encoding

YYYDDDSSS YYY = 3 chars for year offset from 2000 DDD from 0 to 365 SSS from 0 to

Implementation Ideas

  • Create a DNS server in Python.
  • Use a bit torrent library to download PDZ and PDR files
  • PDS client home folder:
    • pdz folder
    • pdr folder
  • PDS client searches for peer domain data on the pdz and pdr folders. If no file matching the name being looked up is found, the pds client initiates multiple searches (on bittorrent, kademlia, twitter, google, etc) and creates a pdz file for each result found.

Use Cases

single record

PDR - Peer domain record - can be pasted on twitter, discussion forums, web pages, emails and so on

#pdr name:suffix#revision record-type value expiry-date signer digest

  • #pdr magic string
  • record-type can be a, aaaa, cname
  • value can be an ip, standard dns name, other PDS name


#pdr openfarmtech:h2#5 c - elifarley 2afqgwk6
#pdr openfarmtech:h2#5 c - - t9fqj6kf

  • expiry is optional
  • signer is optional

pdz file

a .pdz file has all records of a given domain. A pds client retrieves the file using a dht like kademlia, bittorrent or other p2p apps. Users can also save such files in a specific folder called pdz, which should be shared with everyone.


See Also